Objectives: In Southern Qinling Mountains, a large number of postcollisional granite emplacements, most of the granites belongs to high K calcalkali series, its geochemical characteristics shows high Sr and lower Y, just like adakite. Extensive research has been carried out by predecessors,but there are still different opinions. Zaomulan granitic pluton is one of them, but lack of systematic research. We study LAICPMS zircon UPb dating, geochemistry and its geological implications. In order to provide information for regional tectonic evolution. Methods: Base on detailed field geological survey, we choose 7 samples of Zaomulan granitic pluton. A systematic study is carried out on LAICPMS zircon UPb dating and geochemistry. According to the analysis result, combining with regional geologic data, we discussed the regional tectonic evolution. Results: Resarch shows the main body is quartz diorite, Lower SiO2(53.72%～62.21%),Higher MgO（3.84%～7.19%）,High Mg#(65～70),there are large numbers of durk enclaves in the granitic pluton , belong to metaluminous highK calcalkaline granties. High Sr(402×10-6～811×10-6) and extremely loss Y （5.91×10-6～12.7×10-6, ＜18×10-6）and HREE, the content of Yb is 0.58×10-6～1.22×10-6，less than 1.8×10-6, with high Sr/Y(35～94),which shows the typical geochemical characteristics of high Sr and low Y granite (Adakite) . LAICPMS zircon UPb age is 199±3Ma (MSWD=4.3),Lately in the lately Triassic to early in the Early Jurassic. Conclusions: Zaomulan granitic pluton is consists of quartz diorite, the geochemical characteristics of the pluton belong to metaluminous highK calcalkaline granties. Best explained by deep melting of a thickened lower continental crust，and belong to crust—mantle mixing genesis types. The age of 199±3Ma for Zircons represents the crystalline age of the intrusion. indicate that southern Qinling orogenic belt was still in postcollisional period in 200Ma，and provides the material for the regional tectonic evolution.